PCaPAC2012 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
THCA04	An Update on ConSys Including a New LabVIEW FPGA Based LLRF System	controls, LabView, PLC, cavity	97
	T. Worm, J.S. Nielsen ISA, Aarhus, Denmark
	ConSys, the Windows based control system for ASTRID and ASTRID2, is now a mature system, having been in operation for more than 15 years. All the standard programs (Console, plots, data logging, control setting store/restore etc.) are fully general and are configured through a database or file. ConSys is a standard publisher/subscriber system, where all nodes can act both as client and server. One very strong feature is the easy ability to make virtual devices (devices which do not depend on hardware directly, but combine hardware parameters.) For ASTRID2 a new LabVIEW based Low-Level RF system has been made. This system use a National Instruments NI-PCIe7852R DAQ card, which includes an on-board FPGA and are hosted in a standard PC. The fast (50 kHz) amplitude loop has been implemented on the FPGA, whereas the slower tuning and phase loops are implemented in the real-time system. An operator interface including live plots from the regulation loops are implemented in a host program on Windows. All three levels have been implemented with LabVIEW. The LLRF system is interfaced to ConSys through LabVIEW shared variables.
	Slides THCA04 [2.654 MB]

THPD16	Fast Digital Feedback Control Systems for Accelerator RF System using FPGA	controls, feedback, low-level-rf, cavity	172
	P.S. Bagduwal, P.R. Hannurkar, M. Lad, D. Sharma, N. Tiwari RRCAT, Indore (M.P.), India
	Funding: RRCAT Indore Feedback control system plays important role for proper injection and acceleration of beam in particle accelerators by providing the required amplitude and phase stability of RF fields in accelerating structures. Advanced digital technologies allow development of control systems for RF applications. Digital LLRF system offers inherent advantages like flexibility, adaptability, good repeatability and low drift errors compared to analog system. For feedback control algorithm, I/Q control scheme is used. Properly sampling of down converted IF generates accurate feedback signal and eliminates the need of separate detector for amplitude and phase. Controller is implemented in Vertex-4 FPGA with proper control algorithm which offers fast correction with good accuracy and also controls the amplitude and phase in all four quadrants. Single I/Q modulator work as common correctors for both amplitude and phase. LO signal is derived from RF signal itself to achieve synchronization between RF, LO and FPGA clock. Control system has been successfully tested in laboratory with phase and amplitude stability better then ± 1% and ±1°. With minor modification same systems can be used at any frequencies.

THPD20	RF Distribution and Control System for Accelerators of the VEC-RIB Facility	controls, cavity, feedback, low-level-rf	184
	H.K. Pandey, S. Basak, D.P. Dutta, T.K. Mandi VECC, Kolkata, India A. Kumar, K. P. Ray SAMEER, Kolkata, India
	RIB facility at VECC has several heavy ion linear accelerators like RFQ, two IH-LNACs and one buncher cavity operating at 37.8 MHz and two IH-LINACs with one buncher cavity at 75.6 MHz. Some more RF cavities are being designed at the third harmonic of 37.8 MHz and will be added in the RIB beam line. All the cavities have separate RF power amplifiers with proper amplitude, phase and resonance frequency tuning and control system for efficient and stable operation. The LLRF control system has been operational for the power amplifiers of the existing RF cavities and improved design and development is carried out. The main features of the RF control system are phase and amplitude control of the RF input to the amplifiers and tuning of the RF cavity to the desired resonant frequency with automation using feedback control. It will also have various interlocks for the safety of the load as well as the amplifier. A micro-controller based data acquisition and processing system is being used for control and local/remote operation. The RF distribution system as well as the design details of RF control system will be presented in this paper.
	Poster THPD20 [2.163 MB]

THPD35	Modeling and Simulation of Indus-2 RF Feedback Control System	cavity, simulation, feedback, controls	208
	D. Sharma, P.S. Bagduwal, P.R. Hannurkar, M. Lad, N. Tiwari RRCAT, Indore (M.P.), India
	Funding: RRCAT, Indore, Department of Atomic Energy, Government of India The Indus-2 synchrotron radiation source has four RF stations along with their feedback control systems. For higher beam energy and current operation, amplitude and phase feedback control systems of Indus-2 are being upgraded. To understand the behavior of amplitude and phase control loop under different operating conditions, modeling and simulation of RF feedback control system is done. RF cavity base band quadrature domain model has been created due to its close correspondence with actual implementation and better computational efficiency which make the simulation faster. Correspondence between base band and actual RF cavity model is confirmed by comparing their simulation results. Base band Cavity model was studied under different operating conditions. LLRF feed back control system simulation is done using the same cavity model. Error signals are intentionally generated and response of the closed loops system is observed. With implementation of feedback control loop, broadening in the RF cavity bandwidth was also observed in terms of reduction in cavity fill time. Simulation will help us in optimizing parameters of upgraded LLRF system for higher beam energy and current operation.
	Poster THPD35 [0.698 MB]

THPD46	Simulation Analysis of Analog IQ based LLRF Control of RF Cavity	cavity, controls, simulation, rfq	225
	S. Basak, A. Chakrabarti, H.K. Pandey VECC, Kolkata, India
	This paper presents the simulation analysis and results in Matlab Simulink of the analog Inphase-Quadrature (IQ) based LLRF control of RF cavity voltage. The RF cavity parameters were selected to be one of the RF cavities in our RIB project. All the subsystems in the IQ based RF control were modeled using the Simulink blocks/components. The envelope simulation was carried out using the IQ model of RF cavity. The PI controller was properly tuned to achieve good control performance in time. The simulation graphs showing the time evolution of the RF cavity voltage with a step changes of the input reference signal is presented. The simulation graphs showing the control response time needed to correct a disturbance is presented. Further the effects of beam currents (if not ignored) on the cavity voltage can been studied through the simulation graphs. The simulation results showing the amplitude and phase Bode/Nichols plots of the control loop and the gain and phase margin values obtained from them are presented, which are good enough for stability. Thus the control simulation RF cavity voltage is done in Simulink and the results obtained are presented.
	Poster THPD46 [0.222 MB]

FRCB03	RF Control System for 400 keV RFQ	controls, instrumentation, cavity, monitoring	260
	G. Joshi, T. Ananthkrishnan, S.K. Bharade, P. M. Paresh, C.K. Pithawa, C.I. Sujo BARC, Trombay, Mumbai, India
	An RF control system has been developed for the 400 keV, 350 MHz RFQ coming up at BARC. This single cavity system consists of the functionalities of amplitude stabilization and frequency tracking for both continuous and pulsed mode of operation. The amplitude stabilization is implemented by modulating the attenuation across a fast modulator placed in the drive path. The frequency tracking is achieved by driving the FM port of a signal generator with a signal proportional to the phase shift across the resonator. The whole system is under computer control via CAMAC hardware. The paper describes the system architecture, housing & wiring of the system in a single instrumentation rack and development & testing of computer control.
	Slides FRCB03 [0.484 MB]

FRCC02	A FPGA Based High Speed Data Acquisition Card	controls, cavity, pick-up, heavy-ion	271
	J.A. Gore, P. V. Bhagwat, A. Chatterjee, S. Kailas, S. Kulkarni, K. Mahata, S.K. Pandit, V.V. Parkar, A. Shrivastava BARC, Mumbai, India
	Funding: Bhabha Atomic Research Centre, Nuclear Physics Division A FPGA based, high speed,two channel,analog input card with a maximum input sampling rate of 1 Giga samples per second (Gsps)per channel has been designed and tested. The card has got an on-board cPCI interface but has been designed in a way that it can also work as a stand-alone system. The card can function as a platform for developing and evaluating different FPGA based hardware designs. Recently, the card has been used to develop a direct sampling Low Level RF (LLRF) controller for controlling the electromagnetic fields of a prototype heavy ion RFQ. It has also been tested for acquisition of data in nuclear physics experiments. Pulses from surface barrier and silicon strip detectors were acquired at an input sampling rate of 1 Gs/s employing ²⁴¹Am and Am-Pu sources. The design developed for this makes use of pre-triggering. This paper discusses the functionality, salient design issues and features of the card. Finally the hardware designs of above mentioned applications related to different areas of LLRF control and nuclear pulse acquisition are explained and the results obtained are presented.
	Slides FRCC02 [1.431 MB]

Paper

Title

Other Keywords

Page

THCA04

An Update on ConSys Including a New LabVIEW FPGA Based LLRF System

controls, LabView, PLC, cavity

97

T. Worm, J.S. Nielsen
ISA, Aarhus, Denmark

ConSys, the Windows based control system for ASTRID and ASTRID2, is now a mature system, having been in operation for more than 15 years. All the standard programs (Console, plots, data logging, control setting store/restore etc.) are fully general and are configured through a database or file. ConSys is a standard publisher/subscriber system, where all nodes can act both as client and server. One very strong feature is the easy ability to make virtual devices (devices which do not depend on hardware directly, but combine hardware parameters.) For ASTRID2 a new LabVIEW based Low-Level RF system has been made. This system use a National Instruments NI-PCIe7852R DAQ card, which includes an on-board FPGA and are hosted in a standard PC. The fast (50 kHz) amplitude loop has been implemented on the FPGA, whereas the slower tuning and phase loops are implemented in the real-time system. An operator interface including live plots from the regulation loops are implemented in a host program on Windows. All three levels have been implemented with LabVIEW. The LLRF system is interfaced to ConSys through LabVIEW shared variables.

Slides THCA04 [2.654 MB]

THPD16

Fast Digital Feedback Control Systems for Accelerator RF System using FPGA

controls, feedback, low-level-rf, cavity

172

P.S. Bagduwal, P.R. Hannurkar, M. Lad, D. Sharma, N. Tiwari
RRCAT, Indore (M.P.), India

Funding: RRCAT Indore
Feedback control system plays important role for proper injection and acceleration of beam in particle accelerators by providing the required amplitude and phase stability of RF fields in accelerating structures. Advanced digital technologies allow development of control systems for RF applications. Digital LLRF system offers inherent advantages like flexibility, adaptability, good repeatability and low drift errors compared to analog system. For feedback control algorithm, I/Q control scheme is used. Properly sampling of down converted IF generates accurate feedback signal and eliminates the need of separate detector for amplitude and phase. Controller is implemented in Vertex-4 FPGA with proper control algorithm which offers fast correction with good accuracy and also controls the amplitude and phase in all four quadrants. Single I/Q modulator work as common correctors for both amplitude and phase. LO signal is derived from RF signal itself to achieve synchronization between RF, LO and FPGA clock. Control system has been successfully tested in laboratory with phase and amplitude stability better then ± 1% and ±1°. With minor modification same systems can be used at any frequencies.

THPD20

RF Distribution and Control System for Accelerators of the VEC-RIB Facility

controls, cavity, feedback, low-level-rf

184

H.K. Pandey, S. Basak, D.P. Dutta, T.K. Mandi
VECC, Kolkata, India
A. Kumar, K. P. Ray
SAMEER, Kolkata, India

RIB facility at VECC has several heavy ion linear accelerators like RFQ, two IH-LNACs and one buncher cavity operating at 37.8 MHz and two IH-LINACs with one buncher cavity at 75.6 MHz. Some more RF cavities are being designed at the third harmonic of 37.8 MHz and will be added in the RIB beam line. All the cavities have separate RF power amplifiers with proper amplitude, phase and resonance frequency tuning and control system for efficient and stable operation. The LLRF control system has been operational for the power amplifiers of the existing RF cavities and improved design and development is carried out. The main features of the RF control system are phase and amplitude control of the RF input to the amplifiers and tuning of the RF cavity to the desired resonant frequency with automation using feedback control. It will also have various interlocks for the safety of the load as well as the amplifier. A micro-controller based data acquisition and processing system is being used for control and local/remote operation. The RF distribution system as well as the design details of RF control system will be presented in this paper.

Poster THPD20 [2.163 MB]

THPD35

Modeling and Simulation of Indus-2 RF Feedback Control System

cavity, simulation, feedback, controls

208

D. Sharma, P.S. Bagduwal, P.R. Hannurkar, M. Lad, N. Tiwari
RRCAT, Indore (M.P.), India

Funding: RRCAT, Indore, Department of Atomic Energy, Government of India
The Indus-2 synchrotron radiation source has four RF stations along with their feedback control systems. For higher beam energy and current operation, amplitude and phase feedback control systems of Indus-2 are being upgraded. To understand the behavior of amplitude and phase control loop under different operating conditions, modeling and simulation of RF feedback control system is done. RF cavity base band quadrature domain model has been created due to its close correspondence with actual implementation and better computational efficiency which make the simulation faster. Correspondence between base band and actual RF cavity model is confirmed by comparing their simulation results. Base band Cavity model was studied under different operating conditions. LLRF feed back control system simulation is done using the same cavity model. Error signals are intentionally generated and response of the closed loops system is observed. With implementation of feedback control loop, broadening in the RF cavity bandwidth was also observed in terms of reduction in cavity fill time. Simulation will help us in optimizing parameters of upgraded LLRF system for higher beam energy and current operation.

Poster THPD35 [0.698 MB]

THPD46

Simulation Analysis of Analog IQ based LLRF Control of RF Cavity

cavity, controls, simulation, rfq

225

S. Basak, A. Chakrabarti, H.K. Pandey
VECC, Kolkata, India

This paper presents the simulation analysis and results in Matlab Simulink of the analog Inphase-Quadrature (IQ) based LLRF control of RF cavity voltage. The RF cavity parameters were selected to be one of the RF cavities in our RIB project. All the subsystems in the IQ based RF control were modeled using the Simulink blocks/components. The envelope simulation was carried out using the IQ model of RF cavity. The PI controller was properly tuned to achieve good control performance in time. The simulation graphs showing the time evolution of the RF cavity voltage with a step changes of the input reference signal is presented. The simulation graphs showing the control response time needed to correct a disturbance is presented. Further the effects of beam currents (if not ignored) on the cavity voltage can been studied through the simulation graphs. The simulation results showing the amplitude and phase Bode/Nichols plots of the control loop and the gain and phase margin values obtained from them are presented, which are good enough for stability. Thus the control simulation RF cavity voltage is done in Simulink and the results obtained are presented.

Poster THPD46 [0.222 MB]

FRCB03

RF Control System for 400 keV RFQ

controls, instrumentation, cavity, monitoring

260

G. Joshi, T. Ananthkrishnan, S.K. Bharade, P. M. Paresh, C.K. Pithawa, C.I. Sujo
BARC, Trombay, Mumbai, India

An RF control system has been developed for the 400 keV, 350 MHz RFQ coming up at BARC. This single cavity system consists of the functionalities of amplitude stabilization and frequency tracking for both continuous and pulsed mode of operation. The amplitude stabilization is implemented by modulating the attenuation across a fast modulator placed in the drive path. The frequency tracking is achieved by driving the FM port of a signal generator with a signal proportional to the phase shift across the resonator. The whole system is under computer control via CAMAC hardware. The paper describes the system architecture, housing & wiring of the system in a single instrumentation rack and development & testing of computer control.

Slides FRCB03 [0.484 MB]

FRCC02

A FPGA Based High Speed Data Acquisition Card

controls, cavity, pick-up, heavy-ion

271

J.A. Gore, P. V. Bhagwat, A. Chatterjee, S. Kailas, S. Kulkarni, K. Mahata, S.K. Pandit, V.V. Parkar, A. Shrivastava
BARC, Mumbai, India

Funding: Bhabha Atomic Research Centre, Nuclear Physics Division
A FPGA based, high speed,two channel,analog input card with a maximum input sampling rate of 1 Giga samples per second (Gsps)per channel has been designed and tested. The card has got an on-board cPCI interface but has been designed in a way that it can also work as a stand-alone system. The card can function as a platform for developing and evaluating different FPGA based hardware designs. Recently, the card has been used to develop a direct sampling Low Level RF (LLRF) controller for controlling the electromagnetic fields of a prototype heavy ion RFQ. It has also been tested for acquisition of data in nuclear physics experiments. Pulses from surface barrier and silicon strip detectors were acquired at an input sampling rate of 1 Gs/s employing ²⁴¹Am and Am-Pu sources. The design developed for this makes use of pre-triggering. This paper discusses the functionality, salient design issues and features of the card. Finally the hardware designs of above mentioned applications related to different areas of LLRF control and nuclear pulse acquisition are explained and the results obtained are presented.

Slides FRCC02 [1.431 MB]